Linguists spend a lot of paper describing what other linguists said about something. It's common so see a sentence like this in a publication: ''The idea that the syntactic frammistan was a co-paradigmatic member of the relational tier was first suggested by Smith (1924), and supported by...'' (All content has been surgically removed from the preceding quote.)

In itself, this is fine. The trouble comes when someone reads that paraphrase and uses it as the basis for their own paraphrase. Now, no one should be doing that without reading the original source, but (a) people do cut corners occasionally, and (b) even if you read the original source, you may still be affected by the paraphrased version. (Especially, for instance, if the paraphrase is well-written and captures the main idea in a very compact form.)

So, after several generations of this, it's easily possible for the original meaning to become lost. Or, more commonly, the original idea gets simplified and gently warped towards the dominant paradigm. If you keep your eyes open, it's not hard to find cases where -- by the time something gets into the textbooks -- it has changed quite a bit from the original research.

So, to minimize this problem, you'd like to keep your paraphrase as close as possible to the original author's text. You'd even like to use some of his/her words and phrases, if possible. But, of course you need to make it clear that the words are a close paraphrase and not a quote or not your own.